1. Field of the Invention
The present invention relates generally to material delivery systems for agricultural products, including fertilizers, nutrients, crop protection chemicals, biologicals, plant growth regulators; and, more particularly to material dispensing systems for dispensing agricultural liquid products at relatively low rates.
2. Description of the Related Art
Most agricultural liquid products applied at planting are applied generally using water as the carrier, but other carriers may be used such as liquid fertilizers, at rates of the carrier above two gallons per acre. Applying the agricultural liquid products in the carrier at rates below two gallons per acre causes metering problems with the row planter unit that dispenses these agricultural liquid products. One issue is that dispensing agricultural liquid products in a carrier at these low rates requires a relatively small orifice for metering with a standard liquid dispensing system. The small orifice results in concomitant issues with plugging and limits the products that maybe applied at these low rates. The small orifices become more easily plugged by contaminates and particulates if a low rate of dispensing is involved.
Using selective applicators to control weeds growing above the crop has been widely adopted as a weed control method. Several types have been developed. Among them are recirculating sprayers, roller applicators, carpet wipers, and rope wick applicators of several designs. A discussion of rope wick applicators is in the publication “Rope Wick Tips”, by Dennis R. Gardisser, Cooperative Extension Service, University of Arkansas, U.S. Department of Agriculture, and County Government Cooperating, Publication MP229, undated. A rope wick applicator works the way the name suggests. The chemical is wicked from a reservoir to the exposed portion of the rope. This exposed portion of rope is then wiped against the plant to be controlled.
There are several systems used on typical agricultural sprayers that pulse the liquid at three to twenty times a second. This range of pulse rate provides a high degree of control of application. For a given nozzle size and/or application rate the range of speed of travel is more limited if one is not pulsing the application of the agricultural product than if one is pulsing the application. By applying the principals of the present invention, as will be disclosed below, the amount of carrier to apply the pesticides, etc. at planting, can be reduced. The amount of agricultural product can also be reduced.
In some embodiments of the present invention, the spray nozzle of the dispensing system of the row planter unit is modified, as will be disclosed below, to provide a continuous line of agricultural liquid products. In other embodiments, where, what is known in this field as a seed firmer or rebounder is used, features are provided to work with such a low rate of dispensing. Seed firmers and rebounders are used to better place the seed in the bottom of the seed furrow or trench.